/*
 * Copyright (c) 2007-2012, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 */
/*
 * Copyright 1999-2004 The Apache Software Foundation.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
/*
 * $Id: FunctionDef1Arg.java,v 1.2.4.1 2005/09/14 20:18:42 jeffsuttor Exp $
 */
package com.sun.org.apache.xpath.internal.functions;

import com.sun.org.apache.xalan.internal.res.XSLMessages;
import com.sun.org.apache.xml.internal.dtm.DTM;
import com.sun.org.apache.xml.internal.utils.XMLString;
import com.sun.org.apache.xpath.internal.XPathContext;
import com.sun.org.apache.xpath.internal.objects.XString;
import com.sun.org.apache.xpath.internal.res.XPATHErrorResources;

/**
 * Base class for functions that accept one argument that can be defaulted if
 * not specified.
 * @xsl.usage advanced
 */
public class FunctionDef1Arg extends FunctionOneArg {
    static final long serialVersionUID = 2325189412814149264L;

    /**
     * Execute the first argument expression that is expected to return a
     * nodeset.  If the argument is null, then return the current context node.
     *
     * @param xctxt Runtime XPath context.
     *
     * @return The first node of the executed nodeset, or the current context
     *         node if the first argument is null.
     *
     * @throws javax.xml.transform.TransformerException if an error occurs while
     *                                   executing the argument expression.
     */
    protected int getArg0AsNode(XPathContext xctxt) throws javax.xml.transform.TransformerException {

        return (null == m_arg0) ? xctxt.getCurrentNode() : m_arg0.asNode(xctxt);
    }

    /**
     * Tell if the expression is a nodeset expression.
     * @return true if the expression can be represented as a nodeset.
     */
    public boolean Arg0IsNodesetExpr() {
        return (null == m_arg0) ? true : m_arg0.isNodesetExpr();
    }

    /**
     * Execute the first argument expression that is expected to return a
     * string.  If the argument is null, then get the string value from the
     * current context node.
     *
     * @param xctxt Runtime XPath context.
     *
     * @return The string value of the first argument, or the string value of the
     *         current context node if the first argument is null.
     *
     * @throws javax.xml.transform.TransformerException if an error occurs while
     *                                   executing the argument expression.
     */
    protected XMLString getArg0AsString(XPathContext xctxt) throws javax.xml.transform.TransformerException {
        if (null == m_arg0) {
            int currentNode = xctxt.getCurrentNode();
            if (DTM.NULL == currentNode)
                return XString.EMPTYSTRING;
            else {
                DTM dtm = xctxt.getDTM(currentNode);
                return dtm.getStringValue(currentNode);
            }

        } else
            return m_arg0.execute(xctxt).xstr();
    }

    /**
     * Execute the first argument expression that is expected to return a
     * number.  If the argument is null, then get the number value from the
     * current context node.
     *
     * @param xctxt Runtime XPath context.
     *
     * @return The number value of the first argument, or the number value of the
     *         current context node if the first argument is null.
     *
     * @throws javax.xml.transform.TransformerException if an error occurs while
     *                                   executing the argument expression.
     */
    protected double getArg0AsNumber(XPathContext xctxt) throws javax.xml.transform.TransformerException {

        if (null == m_arg0) {
            int currentNode = xctxt.getCurrentNode();
            if (DTM.NULL == currentNode)
                return 0;
            else {
                DTM dtm = xctxt.getDTM(currentNode);
                XMLString str = dtm.getStringValue(currentNode);
                return str.toDouble();
            }

        } else
            return m_arg0.execute(xctxt).num();
    }

    /**
     * Check that the number of arguments passed to this function is correct.
     *
     * @param argNum The number of arguments that is being passed to the function.
     *
     * @throws WrongNumberArgsException if the number of arguments is not 0 or 1.
     */
    public void checkNumberArgs(int argNum) throws WrongNumberArgsException {
        if (argNum > 1)
            reportWrongNumberArgs();
    }

    /**
     * Constructs and throws a WrongNumberArgException with the appropriate
     * message for this function object.
     *
     * @throws WrongNumberArgsException
     */
    protected void reportWrongNumberArgs() throws WrongNumberArgsException {
        throw new WrongNumberArgsException(XSLMessages.createXPATHMessage(XPATHErrorResources.ER_ZERO_OR_ONE, null)); //"0 or 1");
    }

    /**
     * Tell if this expression or it's subexpressions can traverse outside
     * the current subtree.
     *
     * @return true if traversal outside the context node's subtree can occur.
     */
    public boolean canTraverseOutsideSubtree() {
        return (null == m_arg0) ? false : super.canTraverseOutsideSubtree();
    }
}
